Sun City RWRF - Executive Summary |
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RISK MANAGEMENT PLAN - SUN CITY RWRF EXECUTIVE SUMMARY Eastern Municipal Water District (EMWD) has established a risk management plan according to EPA's regulations (40 CFR Part 68) to enhance already existing safety and emergency response programs. EMWD is extremely cautious in the handling of all chemicals and is very diligent about safety for its employees and its communities. EMWD staff is highly trained and utilizes modern equipment to monitor its facilities to provide safeguards, while effectively employing these useful chemicals. These chemicals play an important role in water treatment and water reclamation, enabling everyone to lead healthier lives. Accidental Release Prevention and Emergency Response Policies Eastern Municipal Water District has an emergency response plan in effect to handle potential emergency situations at the Sun City Regional Water Reclamation Facility (RWRF). This Emergency Response Plan was designed to meet the following objectives: 1.) To save lives. 2.) To minimize and avoid injuries. 3.) To protect the environment. 4.) To minimize property damage. The Eastern Municipal Water District Safety Officer is the designated emergency coordinator for the facility. The District also maintains an on-call Emergency Response Team. The Plan provides the response organization and notification procedures, evacuation routes, chlorine health hazards and mitigation procedures which will be implemented to respond effectively to emergency situations that may arise at the facility. This Plan is reviewed and updated at least once per year and has been reviewed and updated to ensure compliance with the PSM, RMP and CalARP regulations Stationary Source and Regulated Substance The Sun City RWRF maintains a maximum quantity of 16,000 pounds of chlorine on-site for use in disinfecting wastewater treated by the plant. There is a single chlorination building located at the facility housing eight one-ton chlorine containers. These containers ar e owned, maintained and filled by the chlorine chemical vendor per Department of Transportation regulations and standards. Chlorine gas is supplied from the bulk tanks to two chlorinators that regulate the chlorine feed rate via a pressure regulating valve that shuts off upon loss of vacuum downstream. A vacuum is created at the chlorinators by water flow through a set of injectors. A chlorine scrubber is connected to the chlorine building. Its sole function is to remove chlorine gas from the room in case of an accidental release from the system. The scrubber is automatically activated by the chlorine detectors that are installed in the room. At 1ppm the detector sounds an alarm in the central control room of EMWD and at 3 ppm the scrubber system is activated. In the scrubber, the chlorine gas is reacted with sodium hydroxide. The result of which is water and table salt. Hazard Assessment Summary Worst Case Release Result Summary Scenario Description: Release of the maxim um quantity of chlorine that can be stored in the largest vessel - 2,000 pounds in 10 minutes. The ton-container is located in a building, therefore, this passive mitigation measure was incorporated in the calculations. The most pessimistic meteorological conditions were used: 1.5 meters/second wind speed, and F stability (a measure for turbulence in the air). Although the chlorination building is equipped with an automatically actuated scrubber system, it was considered to be inoperable for the purposes of this worst case scenario. The reference chart included in EPA's RMP Guidance for Wastewater Treatment Plants was used to determine the maximum downwind distance to 3 ppm. With these assumptions in place, the toxic plume extends offsite. Alternative Release Result Summary Scenario Description: Two alternate scenarios were considered. The first consisted of a liquid release inside the chlorination building from a failure of a fusible plug with a release rate of 150 pounds per m inute from a < inch hole. In the second scenario it is assumed that the vendor delivers a ton-container that has a leaking valve. In both alternate release scenarios, the downwind distances are substantially less than that of the worst case. However, they extend offsite as well. Accidental Release Prevention Program and Chemical-Specific Prevention Steps The Eastern Municipal Water District has a Process Safety Management program in place to manage the handling of chlorine. In addition, common industry standards, policies, and procedures are utilized to ensure safe practices are being performed, including common practices outlined by the Chlorine Institute. In addition to the Management Programs, there are chlorine leak detectors situated in all rooms that contain chlorine. In the event of a chlorine gas leak reaching 1 ppm, the detectors relay a signal that activates a horn and a light outside the room where chlorine has been detected. In addition, the alarm is displayed on the SCADA monitors. At 3 ppm, the alarm signal actuates the emergency scrubber system for the chlorination building. Five Year Accident History The five-year accident history (June 1994 through June 1999) for the Sun City RWRF reveals that there were no incidents that involved a release of chlorine. Planned Changes to Improve Safety Several process and management system improvements were implemented during the development of the PSM Program for this site. For compliance with RMP regulations additional improvements are being considered. |